Papers - Takahashi, Hidetoshi

MEMS two-axis force plate array used to measure the ground reaction forces during the running motion of an ant

H Takahashi, N Thanh-Vinh, UG Jung, K Matsumoto, I Shimoyama

Journal of Micromechanics and Microengineering 24 (6), 065014 (IOP PUBLISHING LTD)  24 ( 6 ) 065014 2014

Joint Work, Accepted,  ISSN  09601317

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A terrestrial insect can perform agile running maneuvers. However, the balance of ground reaction forces (GRFs) between each leg in an insect have remained poorly characterized. In this report, we present a micro force plate array for the simultaneous measurement of the anterior and vertical components of GRFs of multiple legs during the running motion of an ant. The proposed force plate, which consists of a 2000 mu m x 980 mu m x 20 mu m plate base as the contact surface of an ant's leg, and the supported beams with piezoresistors on the sidewall and surface are sufficiently compact to be adjacently arrayed along the anterior direction. Eight plates arrayed in parallel were fabricated on the same silicon-on-insulator substrate to narrow the gap between each plate to 20 mu m. We compartmented the plate surface into 32 blocks and evaluated the sensitivities to two-axis forces in each block so that the exerted forces could be detected wherever a leg came into contact. The force resolutions in both directions were under 1 mu N within +/- 20 mu N. Using the fabricated force plate array, we achieved a simultaneous measurement of the GRFs of three legs on one side while an ant was running.

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Direct measurement of the interaction forces during the sliding of a water droplet on a pillar-typed superhydrophobic surface

TV Nguyen, H Takahashi, K Matsumoto, I Shimoyama

APS Meeting Abstracts  2014

A smart, intermittent driven particle sensor with an airflow change trigger using a lead zirconate titanate (PZT) cantilever

H Takahashi, Y Tomimatsu, T Kobayashi, A Isozaki, T Itoh, R Maeda, ...

Measurement Science and Technology 25 (2), 025103 (IOP PUBLISHING LTD)  25 ( 2 ) 025103 2014

Research paper (scientific journal), Joint Work, Accepted,  ISSN  09570233

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This paper reports on a smart, intermittent driven particle sensor with an airflow trigger. A lead zirconate titanate cantilever functions as the trigger, which detects an airflow change without requiring a power supply to drive the sensing element. Because an airflow change indicates that the particle concentration has changed, the trigger switches the optical particle counter from sleep mode to active mode only when the particle concentration surrounding the sensor changes. The sensor power consumption in sleep mode is 100 times less than that in the active mode. Thus, this intermittent driven method significantly reduces the total power consumption of the particle sensor. In this paper, we fabricate a prototype of the particle sensor and demonstrate that the optical particle counter can be switched on by the fabricated trigger and thus that the particle concentration can be measured.

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Tunable metamaterials by controlling sub-micron gap for the THz range

A Isozaki, T Kan, H Takahashi, N Kanda, N Nemoto, K Konishi, ...

2014 IEEE 27th International Conference on Micro Electro Mechanical Systems … (Proceedings of the IEEE International Conference on Micro Electro Mechanical Systems (MEMS))     1221 - 1224 2014

ISSN  9781479935086

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We propose a tunable metamaterial actuated by pneumatic force. The unit of the proposed metamaterial has a pair of sprit-ring-resonators (SRR), and the gap between them is controllable around sub-micron-order in size. One SRR is formed on a thin cantilever, which can be bent due to differential pressure between the upper and lower surfaces of the cantilever, whereas the other is fixed on a thin membrane. We confirmed that controlling the gap ranging from sub-micron-order to a few-micron-order was suitable for tuning a resonant frequency of a terahertz metamaterial. © 2014 IEEE.

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Traction force of smooth muscle cell during growth on a rigid substrate

UG Jung, T Tsukagoshi, H Takahashi, T Kan, K Matsumoto, I Shimoyama

Micro Electro Mechanical Systems (MEMS), 2014 IEEE 27th International … (Proceedings of the IEEE International Conference on Micro Electro Mechanical Systems (MEMS))     290 - 293 2014

ISSN  9781479935086

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This paper reports on the sensor for traction force measurement of a smooth muscle cell during cell growth on a rigid substrate, specially designed for horizontal and vertical directional forces. For quantitative measurement, the cells are cultured only on the sensor pads using a cover chip. The length of the sensor is 1130μm. The size of the sensor pad is 125μm×15μ m×5μm (length×width× thickness). The gaps between the sensor pads are 3μm. We confirmed that the cells spread on the two sensor pads at least. We measured the traction forces of bovine aortic smooth muscle cells (BAOSMCs, CAB35405) using the proposed sensor. When the three cells spread on the pads, the measured traction forces in x and z direction increased 30nN and 20nN for 8 min, respectively. © 2014 IEEE.

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High-sensitivity triaxial tactile sensor with elastic microstructures pressing on piezoresistive cantilevers

N Thanh-Vinh, N Binh-Khiem, H Takahashi, K Matsumoto, I Shimoyama

Sensors and Actuators A: Physical 215, 167-175 (ELSEVIER SCIENCE SA)  215   167 - 175 2014

Joint Work, Accepted,  ISSN  09244247

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In this paper, we proposed a design to increase the sensitivity of a piezoresistive-type triaxial tactile sensor. Using conventional piezoresistive tactile sensors, in which the piezoresistive elements were completely embedded inside an elastic block, our proposed tactile sensor design features an air cavity underneath the piezoresistive elements. The cavity was created by pressing an elastic cap with microstructures onto the piezoresistive cantilevers of a sensor chip. We confirmed that the proposed design increased the sensitivity of the tactile sensor by approximately 150 times and 100 times in response to normal and lateral forces, respectively. (C) 2013 Elsevier B.V. All rights reserved.

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Interaction forces during the sliding of a water droplet on a textured surface

N Thanh-Vinh, H Takahashi, K Matsumoto, I Shimoyama

2014 IEEE 27th International Conference on Micro Electro Mechanical Systems … (Proceedings of the IEEE International Conference on Micro Electro Mechanical Systems (MEMS))     979 - 982 2014

ISSN  9781479935086

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We have directly measured the interaction forces (in normal and lateral directions) during the sliding of a water droplet on a surface decorated with a micropillar array. The measurement was carried out using a MEMS-based two-axis force sensor array. The advantages of our sensor array were the high sensitivity and miniaturized size of the ultrathin cross-shaped piezo-resistive silicon structure fabricated under a micropillar to detect both the normal and lateral forces acting on the micropillar. A demonstrating measurement using a water droplet with volume of 18 μL sliding on the micropillar array was carried out. The measurement results showed a fluctuation in the interaction forces when the micropillar was close to the trailing edge or leading edge of the droplet. Meanwhile, in the inner region of the contact line, both the normal and lateral interaction forces were relatively stable. These results indicate that the interaction forces at the edges of the droplet are important factors controlling the sliding motion of the droplet. © 2014 IEEE.

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Long stroke out-of-plane actuator using combination of electrostatic and pneumatic forces

T Kan, A Isozaki, H Takahashi, K Matsumoto, I Shimoyama

2014 IEEE 27th International Conference on Micro Electro Mechanical Systems … (Proceedings of the IEEE International Conference on Micro Electro Mechanical Systems (MEMS))     913 - 916 2014

ISSN  9781479935086

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We propose an out-of-plane MEMS actuator with a large stroke length comparable to the size of the actuator itself. The proposed device is actuated by the combined forces of the electrostatic and the pneumatic forces. This combination of two independent forces enlarges a stable area during the actuation, resulting in a large stroke which is difficult to be achieved with only either force. The 3D profiling by the laser scanning microscopy confirmed the largest stroke of 103 μm was obtained with the 150-μm-diameter actuator area with the electric field of 5.8 × 105 V/m (330V between the electrodes) and the air pressure of 2.0 kPa. © 2014 IEEE.

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Measuring differential pressures with multiple MEMS sensors during takeoff of an insect-like ornithopter

H TAKAHASHI, K SATO, K MATSUMOTO, I SHIMOYAMA

Journal of Biomechanical Science and Engineering 9 (1), JBSE0004-JBSE0004 (Japan Society of Mechanical Engineers)  9 ( 1 ) JBSE0004 2014

Joint Work, Accepted,  ISSN  18809863

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In this study, the differential pressure distribution on the wing surface of an insect-like ornithopter was measured directly. Three microelectromechanical system (MEMS) differential pressure sensors were attached to a wing surface in the spanwise direction. The wing length, flapping frequency, and total weight of the ornithopter were 110 mm, 15 Hz, and 7.1 g, respectively. The attachment points corresponded to 25%, 50% and 75% of the wing length and 20% of the length of the wing chord. The ornithopter took offin anterosuperior mode without yawing or rolling. At takeoff, the flapping motion of the wing induced a periodic differential pressure between the upstroke and downstroke. The average values of the maximum differential pressures were 23.5 ± 3.5 Pa, 45.2 ± 3.4 Pa, and 96.7 ± 10.0 Pa at the wing root (WR), wing center (WC), and wing tip (WT), respectively. The maximum differential pressures shifted from the WT to WR in the spanwise direction. These results reflected the aerodynamic forces acting on the insect-like ornithopter during takeoff. © 2014 The Japan Society of Mechanical Engineers.

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Mechanical properties of few layer graphene cantilever

K Matsui, A Inaba, Y Oshidari, Y Takei, H Takahashi, T Takahata, ...

2014 IEEE 27th International Conference on Micro Electro Mechanical Systems … (Proceedings of the IEEE International Conference on Micro Electro Mechanical Systems (MEMS))     1087 - 1090 2014

ISSN  9781479935086

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We report the resonant frequency measurement of few-layer (1-, 2-, and 3-layer) graphene (FLG) cantilevers by optical heterodyne interferometry. The micro-sized FLG cantilevers with and without the diamond-like carbon weights were fabricated using focused ion beam. The Young's modulus was able to be calculated from the measured resonant frequency. The calculated Young's modulus was larger than the literature data [1]. This result suggests that the overlapped structure of the FLG cantilever makes the structure rigid. © 2014 IEEE.

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Design and Fabrication of MEMS Tunable Metamaterials with Sub-micron Gap

A ISOZAKI, T KAN, H TAKAHASHI, N NEMOTO, K KONISHI, ...

電気学会マイクロマシン・センサシステム研究会資料, 71-75 MSS-14 ( 1-4.6-23 ) 71 - 75 2014

A piezoelectric cantilever with a Helmholtz resonator for sound-triggered wake-up switch

Yutaka Tomimatsu, Hidetoshi Takahashi, Takeshi Kobayashi, Kiyoshi Matsumoto, Isao Shimoyama

Journal of Micromechanics and Microengineering 23 ( 11 ) 114003 2013.10

Research paper (scientific journal), Joint Work, Accepted

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A piezoelectric flow sensor for use as a wake-up switch for a wireless sensor network node

Yutaka Tomimatsu, Hidetoshi Takahashi, Kenta Kuwana, Takeshi Kobayashi, Kiyoshi Matsumoto, Isao Shimoyama, Toshihiro Itoh and Ryutaro Maeda

Mechatronics (PERGAMON-ELSEVIER SCIENCE LTD)  23 ( 7 ) 893 - 897 2013.10

Research paper (scientific journal), Joint Work, Accepted,  ISSN  0957-4158

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Power management is a fundamental issue in wireless sensor networks. In this paper, a piezoelectric flow sensor is proposed for use as a wake-up switch in a wireless sensor node to reduce power consumption. A cantilever with a Pb (Zr,Ti) O-3 (PZT) thin film detects airflow changes surrounding the wireless sensor node. A prototype of the flow sensor is used to determine the relationship between the change in flow velocity and piezoelectric voltage of the cantilever. The fabricated sensor generates a piezoelectric voltage of several millivolts when the flow velocity changes at a rate of approximately 1 m/s. (C) 2013 Elsevier Ltd. All rights reserved.

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Measurement of an airflow velocity change using a cantilever with Pb(Zr, Ti)O<inf>3</inf>

Tomimatsu Y., Takahashi H., Kuwana K., Kobayashi T., Matsumoto K., Shimoyama I., Itoh T., Maeda R.

2013 Symposium on Design, Test, Integration and Packaging of MEMS/MOEMS, DTIP 2013 (2013 Symposium on Design, Test, Integration and Packaging of MEMS/MOEMS, DTIP 2013)   2013.09

ISSN  9781467344777

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We proposed a thin piezoelectric cantilever to measure an airflow velocity change. An airflow sensor using a PZT cantilever and a flow channel was fabricated. We measured the relationship between the airflow velocity change and the piezoelectric voltage of the cantilever. The dimensions of the sensor and the cantilever are 25 mm × 20 mm × 20 mm and 1500 μm × 1000 μm × 2 μm respectively. We evaluated the effect of the diameter of the flow channel on the sensor response. It was demonstrated that the fabricated sensor generated an output voltage of several millivolts when the airflow velocity changed at a rate of approximately 1 m/s. It was observed that the output voltage increased as the diameter of the flow channel became small. © 2013 CMP.

Micro force plate array for measurement of ground reaction force of insect running

H Takahashi, K Matsumoto, I Shimoyama

Micro Electro Mechanical Systems (MEMS), 2013 IEEE 26th International …    59 - 62 2013

ISSN  1084-6999

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This paper reports on a micro force plate array for measurement of ground reaction forces of insect legs during running. The micro force plate is composed of a plate base and three beams whose surface and sidewall area are doped, which enable to detect both pressure and shear force. The device size and force resolution are 2000 μm × 500 μm × 20 μm (length × width × height) and 1 μN, respectively. Using this force plate array, the ground reaction forces of an ant was able to be measured. © 2013 IEEE.

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Measurement of an airflow velocity change using a cantilever with Pb(Zr, Ti)O3

Y Tomimatsu, H Takahashi, K Kuwana, T Kobayashi, K Matsumoto, ...

2013 Symposium on Design, Test, Integration and Packaging of MEMS/MOEMS …  2013

Effectiveness of bristled wing of thrips

K Sato, H Takahashi, N Minh-Dung, K Matsumoto, I Shimoyama

2013 IEEE 26th International Conference on Micro Electro Mechanical Systems … (IEEE)     21 - 24 2013

ISSN  1084-6999

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We have investigated the mechanism of a bristled wing of thrips by using an artificial cantilever-based wing. Five kinds of the artificial bristled wing, which had the similar size of the thrips wing, with a different hair gap were evaluated in a wind tunnel. Experiment results suggested that at low hair-gap-based Reynolds number (&lt;10), the bristled areas of the wing acted as an imaginary airflow block, which increased the aerodynamic force. Meanwhile, this phenomenon did not occur at high Reynolds number (&gt;100).

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Differential pressure distribution measurement for the development of insect-sized wings

H Takahashi, K Matsumoto, I Shimoyama

Measurement Science and Technology 24 (5), 055304 (IOP PUBLISHING LTD)  24 ( 5 ) 055304 2013

Research paper (scientific journal), Joint Work, Accepted,  ISSN  0957-0233

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This paper reports on the measurement of the differential pressure distribution over a flat, thin wing using a micro-electro-mechanical systems sensor. Sensors featuring a piezoresistive cantilever were attached to a polyimide/Cu wing. Because the weight of the cantilever element was less than 10 ng, the sensor can measure the differential pressure without interference from inertial forces, such as wing flapping motions. The dimensions of the sensor chips and the wing were 1.0 mm x 1.0 mm x 0.3 mm and 100 mm x 30 mm x 1 mm, respectively. The differential pressure distribution along the wing's chord direction was measured in a wind tunnel at an air velocity of 4.0 m s(-1) by changing the angle of attack. It was confirmed that the pressure coefficient calculated by the measured differential pressure distribution was similar to the value measured by a load cell.

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Design of a piezoresistive triaxial force sensor probe using the sidewall doping method

T Kan, H Takahashi, N Binh-Khiem, Y Aoyama, Y Takei, K Noda, ...

Journal of Micromechanics and Microengineering 23 (3), 035027 (IOP PUBLISHING LTD)  23 ( 3 ) 035027 2013

Research paper (scientific journal), Joint Work, Accepted,  ISSN  0960-1317

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In this study, we propose a triaxial force measurement sensor probe with piezoresistors fabricated via sidewall doping using rapid thermal diffusion. The device was developed as a tool for measuring micronewton-level forces as vector quantities. The device consists of a 15 mu m thick cantilever, two sensing beams and four wiring beams. The length and width of the cantilever are 1240 mu m and 140 mu m, respectively, with a beam span of 1200 mu m and a width of 10-15 mu m. The piezoresistors are formed at the root of the cantilever and the sidewalls of the two sensing beams. The sensor spring constants for each axis were measured at k(x) = 1.5 N m(-1), k(y) = 3.5 N m(-1) and k(z) = 0.64 N m(-1). We confirmed that our device was capable of measuring triaxial forces with a minimum detectable force at the submicronewton level.

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An AlN cantilever for a wake-up switch triggered by air pressure change

Y Kaiho, H Takahashi, Y Tomimatsu, T Kobayashi, K Matsumoto, ...

Journal of Physics: Conference Series 476 (1), 012122 (IOP PUBLISHING LTD)  476 2013

ISSN  1742-6588

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This research reports an AlN cantilever with an air chamber for a wake-up switch triggered by air pressure change. The proposed sensor is designed to fulfil both high sensitivity and low power consumption. By combining an air chamber to the one side of the AlN cantilever surface, the barometric pressure change generates a piezoelectric voltage. Thus, a wake-up switch triggered by air pressure change can be achieved using an AlN cantilever. The size of the fabricated AlN cantilever was 2000 mu m x 1000 mu m x 2 mu m. The sensitivity to static differential pressure was 11.5 mV/Pa at the range of -20 Pa to 20 Pa. We evaluated the response of the sensor, which was composed of the AlN cantilever and the chamber of 60 ml in volume, when air pressure change was applied. The output voltage increased with increasing the applied air pressure change. It was observed that the maximum output voltage of 50 mV was generated when the air pressure change was 13 Pa.

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